Unfortunately we will have to buy a DX10.1 card to support all its features, our DX10 cards will still be able to run DX10.1 games, just not with all the features:
From Microsoft's SDK (Software Development Kit) Notes:
Direct3D 10.1 is an incremental, side-by-side update to Direct3D 10.0 that provides a series of new rendering features that will be available in an upcoming generation of graphics hardware.
- TextureCube Arrays which are dynamically indexable in shader code.
- An updated shader model (shader model 4.1).
- The ability to select the MSAA sample pattern for a resource from a palette of patterns, and retrieve the corresponding sample positions.
- The ability to render to block-compressed textures.
- More flexibility with respect to copying of resources.
- Support for blending on all unorm and snorm formats